Did I fry my tach?

[The Griff]

Well since I put my new distributor in a few months ago, I never bothered to hook my tach back up, Today was a nice day so I decided I would, but something is wrong, When I start it up it says its spinning about 600, which is about right (it idles low) but if I get on it at all it will jump to something like 8K, and bounce around for a while, and sometimes smooth out, but completely at random.

It worked fine before, and the whole time it wasn't hooked up the wire just hung next to the distributor, I checked everything a few times over and nothing seems wrong.

What happened to it?

 

[AR_K5]

Did you bump the switch to 4cyl on the tach?

 

[The Griff]

Hmm, that's very possible.

EDIT; But not the problem, its set on 8, anything else it could be?

 

[Kain]

sometime's they just die...

 

[dyeager535]

These things can be rebuilt, for the rarity, I'd look into that option. They sell components to do that, Dad just fixed one of the 80's truck tachs with one of the adjustable pots(? I think that was what it was) sold to fix the bad tachs.

 

[fwc]

Check the pickup coil (not talking about the ICM) in your distributor. When mine went bad it caused the tach to randomly go haywire jumping all over the place as well as but not always making the engine run like crap.

If the *new* distributor is actually a remaned unit there's a good chance that they didn't replace the pickup coil during the refurb.

 

[The Griff]

That's also possible, but like you said, it usually would run crappy, but it doesn't, it runs like an absolute champ.

I actually have a brand new coil sitting on the table next to me, but I really don't want to mess with it right now.

 

[wazzabie]

How to rebuild http://howtoalmanac.com/kevin/projects/automotive/tachfixtruck.htm